Radiation dose reduction in CT fluoroscopy-guided lumbar interlaminar epidural steroid injection by minimizing preliminary planning imaging.

OBJECTIVES

To test whether radiation dose reduction in CTF-guided LIESI would be achieved by replacing the preliminary planning CT with a spot CTF while still maintaining technical performance.

METHODS

This retrospective study included a review of 247 consecutive procedures performed on 241 patients before (comparison group: n = 124) and after (study group: n = 123) instituting the above-mentioned the protocol modification. The patient (age, sex, body diameter, and level injected) and performance (procedure time, number of CTF acquisitions, and DLP) characteristics were compared between the two groups.

RESULTS

The total DLP of the study group (median 4.94 mGy · cm) was significantly reduced compared to that of the comparison group (median 31.78 mGy · cm, P < 0.001). The numbers of CTF acquisitions needed for needle placement and epidurography were very similar for both groups (median 3, P = 0.685). The mean procedure time was significantly shorter for the study group (5:14 ± 1:06 min) compared to the comparison group (5:53 ± 1:19 min, P < 0.001).

CONCLUSIONS

When conducting CTF-guided LIESIs, a significant radiation dose reduction (median 84.5% in DLP, P < 0.001) can be achieved by minimizing the preliminary planning examination, without compromising the number of CTF acquisitions and the procedure time.

KEY POINTS

Majority of radiation is delivered during the preliminary planning image acquisition. Spot CTF scan can replace the preliminary planning helical examination. Patient dose can be reduced to as low as 0.09 mSv.