The pattern of CT-Scan findings in black stroke patients as seen at 2 imaging centres in Nairobi

Abstract

Introduction: Stroke lesions are known to show significant racial and regional variations. Several workers in Africa have found haemorrhagic stroke to make up a much larger proportion of stroke lesions than that reported in the West. The purpose of this study was to describe stroke patterns in Blacks in Nairobi from a radiological perspective using the imaging modality of CT. Objective:

The aim of this study was to determine the pattern of CT scan findings in black adult stroke patients seen at two imaging centers in Nairobi with particular reference to the proportions ofhaemorrhagic and ischaemic lesions. Study design:

This was a descriptive prospective study. Methods:

The brain CT scans of 112 consecutive patients with a clinical diagnosis of stroke done between July and December 2005 in two imaging centers in Nairobi were reviewed. Clinical information provided on the requisition forms was also recorded. The CT scans were evaluated to determine the frequency of infarctive and haemorrhagic lesions as well as their locations, sizes and local anatomical effects. The frequency of non-stroke lesions in these patients was also documented. Correlation was made of the patients' age, sex, and known medical conditions with the topographic findings on CT. Results:

There were 53 (47.3%) male and 59 (52.7%) female patients scanned. The age range was from 16 to 100 years. The mean age for stroke was 61.6 years. The 51 - 60 years and 61 -70 years age brackets had the highest rates of stroke with 30.1 % of patients each. Patients below age 50 years constituted 20.4% while those above age 65 years constituted 47.3%. Stroke was radiologically confirmed in 84% (94) of patients. Nine examinations showed no abnormality on CT. In another nine, disorders other than stroke were found. Of the 94 patients with radiologically confirmed stroke, 68.1% (64) had infarctions, 30.9% (29) had parenchymal haemorrhages and 1.1 % (one) had subarachnoid haemorrhage. The non-stroke disorders found were six subdural haematomas, two high grade gliomas and one case of cerebritis.

Conclusion: The rate of haemorrhagic type of stroke in black adult patients as seen at the two imaging centers in Nairobi is 30.9%. This is about twice that stated by most authors for the largely Caucasian population in the Europe and America. However, it is significantly lower than that demonstrated by earlier studies in Africa which suggested a rate above 50%. The findings of this study concur with those of a similar prospective study done in Zimbabwe in 1986.