Low-dose protocol for head CT in monitoring hydrocephalus in children

Background: Children with hydropcephalus and increased intracranial pressure are treated with ventricular shunts. Multiple head CT is used to assess shunt malfunction and changes in ventricular size (volume). Because of the naturally high contrast of the head structures in CT imaging, a low-dose protocol for hydrocephalic pediatric patients was proposed. The aim of the study was to assess the implemented protocol in categories of radiation risk to the patients.
Material and Methods: Head CT examinations were performed using the fourth-generation single-slice scanner PQ-2000 (Picker). Exposure parameters of the routine head procedure stored in the scanner software were the starting point for the investigation. The acceptable ranges of the modified parameters were found on the basis of earlier published results. The effect of the new protocol on image quality was tested using a CATPHAN phantom. The organ doses were evaluated experimentally. The clinical images were evaluated by two experienced and independent radiologists. Results: Head CT examinations were performed in 380 children with hydrocephalus during a 10-year period at the Department of Diagnostic Imaging Polish Mother’s Memorial Hospital. Until 2005 these children were examined according to the routine protocol of the scanner, i.e. 10 mm contiguous axial, 120 kVp, and 225 mAs. Then the protocol was modified to 10 mm contiguous axial, 100 kVp, and 150 mAs. Reductions in patient doses to 70% were found while the clinical images maintained sufficient diagnostic value. Conclusions: The low-dose protocol for head CT can be recommended for the monitoring of pediatric hydrocephalus patients.

Keywords: Adult, Adolescent, Child, Child, Preschool, Head - radiography, Hydrocephalus - therapy, Infant, Newborn, Intracranial Hypertension - radiography, Radiation Dosage, Tomography, X-Ray Computed - methods, Ventriculoperitoneal Shunt