The role of computerized tomography in the diagnosis of intracranial pathology in children at Kenyatta National Hospital

Abstract

The rapidly growing use of CT scan in paediatrics worldwide carries the potential for increased radiation exposure to children undergoing these scans. This has been associated with small but significant increased risk of carcinogenesis.(l) Large studies have detected this small risk, which appears to be related to the cumulative radiation dose of all previous exposures in a linear fashion.(2).The consensus among paediatric radiologists is that about 30% of paediatric CT examinations are unnecessary.(3) CT head is by far the most commonly performed CT examination among children aged five years and below at KNH.(4) OBJECTIVE The main objective of the study was to determine the role of CT in diagnosis of intracranial pathology in children aged five years and below at KNH. The other objectives were to establish the patient screening practice and to document radiation dose minimization measures practiced at KNH during cranial CT exams on young children. However it was not designed to measure actual absorbed radiation doses. METHODOLOGY This was a prospective cross-sectional study conducted at the Kenyatta National Hospital (Nairobi) which is the main teaching and referral hospital in Kenya. It spanned the six month period from January 2010 to June 2010. The study was performed on a 16 slice multidetector CT scanner, Brilliance model, serial no.729 manufactured by Phillips in January 2007. Data collection was done in the KNH CT scan room, using a well structured data sheet. Data analysis was done by computer using Software Program for Social Science research (SPSS-Pc version 11.0). RESULTS A total of 101 patients were studied. The study group included 65(64.4%) males and 36(35.6%) females. The age distribution ranged from 1- 60 months. 50(49.5%) were inpatients while 51 (50.5%) were outpatients. Only 45% of the cranial CT request forms for patients included in this study were found to have been vetted and signed by a radiologist. The most common indication for cranial CT was convulsions followed by head injury. Convulsions as a cranial CT indication was found to be most common in the under 12 month age group. The most common CT diagnosis was infections and infestations (26.0%) followed by normal scan (lS.()%) Only 6.0% of inpatient referrals had normal scans compared to 29.4% normal scans among outpatient referrals. This could be due to a more effective patient screening system in the inpatient departments. Furthermore inpatients are also likely to have more severe signs and symptoms which would be associated with radiologic signs. Views on the accuracy of the provisional diagnosis given by the referring clinician from the inpatient and outpatient departments are discussed. Although paediatric cranial CT exams at KNH are done according to established routine standard operating procedures(SOPs), this study revealed the lack of a written outline of these SOPs in the radiology department. Subsequently the principal researcher contributed to the development of written SOPs in collaboration with radiologists at the CT section. The study also found that thyroid shielding is not routinely applied during paediatric cranial CT exams at KNH due to shortage of thyroid shields. CONCLUSION CT was found to be a useful and adequate diagnostic tool for intracranial pathology in young children. However it is important for healthcare community to work together to minimize radiation dose to children. Hopefully recommendations based on the findings of this study will help to emphasize to clinicians, technicians and radiologists the need to adopt best practices and techniques aimed towards radiation dose minimization during paediatric cranial CT exams and ensuring that only appropriate or relevant examinations are performed.