Photon-counting computed tomography for paediatric congenital heart defects yields images of high diagnostic quality with low radiation doses at both 70 kV and 90 kV

Abstract

BackgroundPhoton-counting computed tomography (PCCT) is a new clinical method that may show better diagnostic quality at lower radiation doses than conventional CT.ObjectiveTo investigate the diagnostic quality and radiation dose of paediatric cardiovascular PCCT for diagnosis of congenital heart defects at 70 kV and 90 kV.Materials and methodsThis retrospective assessment included clinical non-gated paediatric PCCT examinations for assessment of congenital heart defects. Radiation doses were recorded, and overall and specific diagnostic quality (1–4) were scored by four paediatric radiologists. Agreement, differences, and trends were assessed by percent rater agreement, intraclass correlation, Mann–Whitney tests, and Jonckheere-Terpstra tests.ResultsSeventy children with congenital heart defects were examined at 70 kV (n = 35; age 2 days–16 years; 63% boys) or 90 kV (n = 35; age 2 days–17 years; 51% boys). All observers gave a median score of 4 (high diagnostic quality) for both 70 kV and 90 kV, with no difference in median values between tube voltages (all P > 0.06). Agreement for overall scores was 66–94% for 70 kV and 60–77% for 90 kV. Agreement for specific scores was 80–97% for 70 kV and 83–89% for 90 kV. Size-dependent dose estimate was 0.68 mGy (0.25–2.02 mGy) for 70 kV and 1.10 mGy (0.58–2.71 mGy; P < 0.001) for 90 kV. Effective dose was 0.30 mSv (0.15–0.82 mSv) for 70 kV and 0.39 mSv (0.22–1.51 mSv; P = 0.01) for 90 kV.ConclusionPaediatric cardiovascular PCCT yields images for congenital heart defects of high diagnostic quality with low radiation dose at both 70 kV and 90 kV.