Yannick Laurent Thal

Purpose: In emergency diagnostics, head CT and CT angiography (CTA) of craniocervical vasculature are indispensable for children, despite their increased radiation sensitivity. This study assesses the radiation dose metrics of head CT and CTA in pediatric patients managed in the trauma resuscitation unit (TRU). Methods: All patients aged 0–<15 years who underwent head CT and CTA in the TRU between April 2020 and August 2023 were included. CT dose index volume (CTDIvol) and dose-length product (DLP) were extracted from the Radimetrics Enterprise Platform, which also provided organ doses estimated via Monte Carlo simulations and effective doses (ED) derived from these estimates. Dose metrics were compared with national diagnostic reference levels (DRLs), defined for three pediatric age groups: I (0–<5 years), II (5–<10 years), and III (10–<15 years). Results: Of 212 pediatric TRU patients, 62.7% (133/212) underwent CT and 72.2% (96/133) received combined CT and CTA. Median CTDIvol and DLP increased with age, whereas ED decreased. For head CT, CTDIvol ranged from 18.9 mGy to 29.4 mGy, DLP from 282 to 460 mGycm, and ED from 1.6 to 1.3 mSv. For CTA, CTDIvol ranged from 1.4 to 2.2 mGy, DLP from 40 to 83 mGycm, and ED from 1.0 to 0.8 mSv. All doses remained below national DRLs. Conclusion: Head CT and CTA in pediatric trauma can be performed with radiation doses well below national DRLs. Careful dose management is important to reduce potential long-term cancer risks and deterministic effects such as lens cataract formation.

Purpose: Spinal muscular atrophy (SMA) is a rare neuromuscular disease treated with intrathecal nusinersen. In patients with complex spinal anatomy or spinal instrumentation, repeated lumbar punctures can be challenging. This study evaluated the feasibility, safety, and radiation exposure of CT-guided nusinersen administration in SMA. Methods: In this retrospective single-center study, 458 CT-guided nusinersen injections in 44 SMA patients (October 2017–August 2024) were analyzed. Technical success, complications, procedure and puncture times, and radiation exposure were compared between subgroups. Procedures were performed in prone, lateral, or combined (oblique) positions depending on anatomy. Results: Technical success was 98.3% (449/458). Rates were slightly lower in patients with dorsal spondylodesis (97.1% vs. 98.8%). Complications occurred in 1.1% (5/458), including transient pain and two hematomas. Spondylodesis was associated with longer puncture (11.9 vs. 10.3 min) and procedure durations (16.3 vs. 14.0 min) and higher radiation doses (effective dose 2.22 vs. 1.74 mSv; all p < 0.01). Failed or complicated procedures showed prolonged durations and higher exposure. Needle repositioning correlated with duration and dose. Conclusion: CT-guided lumbar puncture for intrathecal nusinersen injection is a safe and effective technique, even in complex spinal anatomy. Dorsal spondylodesis increases procedural complexity. Tailored puncture level selection, optimized positioning, and dose-reduction strategies are essential for high success rates and minimal radiation. While CT guidance ensures excellent anatomical visualization, fluoroscopy may reduce radiation and procedure time; future comparative studies should define optimal modality selection.