MULTIDETECTOR COMPUTERIZED TOMOGRAPHY SCAN FINDINGS OF THE HEAD IN PATIENTS WITH HEAD INJURY AT KENYATTA NATIONAL HOSPITAL

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INTRODUCTION
Assessment of the critically injured patient is time – dependent and should not delay definitive care, which in many cases requires surgery. Computed tomography has certainly fulfilled that criterion and it has become the most important diagnostic innovation in evaluating head injuries. It has generally replaced insensitive, non specific and difficult to interpret studies with one accurate, simple and non-invasive study3. The use of Multidetector Computed tomography has further improved on this by providing faster acquisition of images, higher spatial resolution and better image quality4.

BACKGROUND
Head injury is a major cause of morbidity and mortality worldwide. The incidence of head injury is 300 per 100,000 per year with a mortality of 25 per 100,000 in North America and 9 per 100,000 in Britain2.

OBJECTIVE
The main objective of the study was to describe the occurrence and pattern of findings of Head Injury on Multidetector Computerized Tomography of the Head in patients seen at Kenyatta National Hospital (KNH). The other objectives were to determine the causes, age and sex distribution, the presenting complaints and radiological findings of head injury and to correlate these findings with the Glasgow Coma Scale (GCS).

METHODOLOGY
The study was conducted at KNH (Nairobi), which is the main Referral Hospital in Kenya. The study was performed on a 16 slice Multidetector CT scanner, Brilliance Model, Serial No.729, manufactured by Phillips, 2007 January. The study was a prospective one and was carried out for a period of 4 months, from July 2008 – October 2008. A total of 192 patients were recruited for the study.

RESULTS
A total of 192 patients were recruited for the study. The patients’ age ranged from 10 months to 85 years. More males (82.3%) were recruited. The male to female ratio was 5:1. The commonest cause of head injury was Road Traffic Accidents (RTA) (51.8%) followed by Assault (27.5%). Main symptom necessitating a Head CT scan following 2
head injury was Loss of Consciousness (54.2%) followed by headache (29.2%) and Confusion(19.3%). The commonest age group affected was 20-29 year (31.3%) followed by 30-39years (29.7%). Most patients had moderate head injury (GCS score 9-13) (50.5%). The most common CT scan finding was Scalp injury (Subgaleal Hematoma) (9.21%), followed by linear skull fracture(9.07%) and diffuse cerebral oedema(8.64%). Patients with moderate and severe head injuries GCS’s of 9-13 and < 8 respectively had severer CT scan findings such as Intraventricular hemorrhages and diffuse axonal injury.

CONCLUSION
Multidetector Computed Tomography (MDCT) was found to be a useful and adequate diagnostic tool in the evaluation of patients presenting with head injury. There was additional pick up of diffuse axonal injury which was not demonstrated on earlier studies done on conventional CT scans. The Glasgow Coma Scale was found to be an important clinical assessment scale in the head injured patient because it is a predictor of severity of injury.