[Evaluation of the Infant Skull via Low-dose CT Images Using an Sn Filter and the Iterative Reconstruction Method].

Purpose: This study aimed to evaluate whether low-dose CT imaging using an Sn filter can provide image quality sufficient for the differential diagnosis of cranial deformities in infants while maintaining an effective dose comparable to that of conventional radiography.

Methods: We calculated the effective dose for both head X-ray imaging and low-dose CT with an Sn filter. Phantom images acquired using a CT scanner equipped with an Sn filter were evaluated for bone suture visibility at various conditions (from 10 mAs to 50 mAs, every 10 mAs) using a 4-point visual grading scale. In addition, a visual assessment of low-dose CT versus standard-dose CT was performed for infants with cranial deformities.

Results: The effective dose for 2-directional X-ray imaging was 0.011 mSv. At 50 mAs, the effective dose for low-dose CT was 0.008 mSv, with good visibility of the bone sutures, showing nearly equivalent effective doses. The visual assessment results did not differ significantly between low-dose CT and normal-dose CT for infants with cranial deformities (P>0.05).

Conclusion: Low-dose CT using an Sn filter can visualize the infant skull at an effective dose equivalent to conventional X-ray imaging, and the image quality was found to be sufficient for the differential diagnosis of cranial deformities.