Comparative analysis of anterior and posterior contrast injection approaches for shoulder MR arthrograms in adolescents

Background: There is no consensus in the literature concerning the optimal approach for performing a fluoroscopically guided shoulder arthrogram injection in a pediatric population. Objective: To compare adequacy of capsular injection and radiation doses between fluoroscopically guided anterior and posterior glenohumeral joint contrast injections in adolescents. Materials and methods: We evaluated imaging in 67 adolescents (39 boys, 28 girls; mean age 16.0 years; range 11.7–19.1 years) who underwent an anterior approach glenohumeral contrast injection with subsequent MR imaging, and 67 age- and gender-matched subjects (39 boys, 28 girls; mean age 16.0 years; range 11.1–19.2 years) who underwent a posterior approach injection during the period June 2010 to September 2015. Two pediatric radiologists independently evaluated all MR shoulder arthrograms to assess adequacy of capsular distention and degree of contrast extravasation. We recorded total fluoroscopic time, dose–area product (DAP) and cumulative air kerma (CAK). Results: There were no significant differences in age, gender, height, weight or body mass index between the populations (P-values > 0.6). The amount of contrast extravasation between the groups was not significantly different (P = 0.27). Three anterior injections (4.5%) and one posterior (1.5%) were suboptimal (P = 0.62). Fluoroscopy time was not different: 1.1 min anterior and 1.3 min posterior (P = 0.14). There was a significant difference in CAK (0.7 mGy anterior and 1.1 mGy posterior; P = 0.007) and DAP (5.3 μGym² anterior and 9.4 μGym² posterior; P = 0.008). Inter-rater agreement was excellent (Cohen kappa >0.81). Conclusion: Both techniques were technically successful. There was no difference in the fluoroscopy time for either approach. The radiation dose was higher with the posterior approach but this is of questionable clinical significance.