White matter changes on magnetic resonance imaging: a risk factor for stroke in an African population?

BACKGROUND: White matter changes are frequently observed incidental findings in elderly individuals. Many studies in Europe and the United States have assessed the association of white matter changes with stroke and other diseases. No similar study has been conducted in sub-Saharan Africa, where risk factors for stroke differ. Our objective was to explore the association between severity of white matter changes (based on visual rating scales) and stroke in a Nigerian population. METHODS: Magnetic resonance imaging (MRI) scans of 50 patients were retrospectively assessed and scored using 3 different visual rating scales (by Fazekas et al, Scheltens et al, and Manolio et al). The scores were classified as either mild or severe. Clinical indications and MRI scan results were classified into vascular (stroke) and nonvascular groups. The association between severity of white matter changes and stroke on MRI was explored using the Student t test, the Chi-square test, and multiple regression analysis at an alpha level of .05. RESULTS: White matter changes were consistently and significantly more severe in patients with stroke than in patients without stroke (.01 ≤ P < .001; odds ratios 4.58 and 13.3, respectively) using the 3 visual rating scales. This finding was independent of age and gender as confirmed by regression analysis (adjusted odds ratios 4.8 and 9.2; .015 ≤ P ≤ .003). CONCLUSIONS: Our findings suggest that severity of white matter changes in Nigerians may be a significant risk factor for stroke independent of age and gender. Prospective larger studies will be required to confirm its role in predicting stroke and stroke recurrence independent of other vascular risk factors, such as hypertension, diabetes, and cardiac diseases.

Incidental cranial CT findings in head injury patients in a Nigerian tertiary hospital.

BACKGROUND: Incidental findings on computed tomography (CT) scans are occasionally noted in patients presenting with head injury. Since it can be assumed that head injured patients are of normal health status before the accident, these findings may be a representation of their frequency in the general population. Our aim was to determine the prevalence of such incidental findings among head injured patients in Nigeria's foremost center of clinical neurosciences. MATERIALS AND METHODS: We conducted a retrospective review of CT scan images of 591 consecutive eligible patients over a 5-year period (2006-2010) to identify incidental findings. The images were evaluated by consensus agreement of two radiologists. Associations with gender and age were explored using appropriate statistical tests with an alpha level of 0.05. RESULTS: The mean patient age was 34.6 ± 21.2 years, and male to female ratio was 3.2: 1. Incidental findings were noted in 503/591 (85.1 %) of the scans. Intracranial calcification was the commonest finding occurring in 61.8% of patients. Over 90% of the findings were benign. Compared with older ones, patients under the age of 60 were less likely, (P < 0.001), to have incidental findings. CONCLUSION: Although the majority of incidental findings in this African cohort of head injury patients are benign some clinically significant lesions were detectable. It is therefore recommended that such findings be adequately described in the radiological reports for proper counseling and follow-up.

Medial temporal lobe atrophy, white matter hyperintensities and cognitive impairment among Nigerian African stroke survivors.

BACKGROUND: Neuroimaging features associated with vascular cognitive impairment have not been examined in sub-Saharan Africans. We determined magnetic resonance imaging (MRI) features associated with cognitive impairment in a sample of Nigerian stroke survivors. METHODS: Stroke survivors underwent brain MRI with standardized assessment of brain volumes and visual rating of medial temporal lobe atrophy (MTA), and white matter hyperintensities (WMH) at 3 months post-stroke. Demographic, clinical and psychometric assessments of global cognitive function, executive function, mental speed and memory were related to changes in structural MRI. RESULTS: In our pilot sample of 58 stroke survivors (60.1 ± 10.7 years old) MTA correlated significantly with age (r = 0.525), WMH (r = 0.461), memory (r = -0.702), executive function (r = -0.369) and general cognitive performance (r = -0.378). On univariate analysis, age >60 years (p = 0.016), low educational attainment (p < 0.001 to p < 0.003), total brain volume (p < 0.024 and p < 0.025) and MTA (p < 0.003 to p < 0.007) but not total WMH (p < 0.073, p = 0.610) were associated with cognitive outcome. In a two-step multivariate regression analysis, MTA (p < 0.035 and p < 0.016) and low educational attainment (p < 0.012 and p < 0.019) were sustained as independent statistical predictors of cognitive outcome. CONCLUSIONS: Medial temporal lobe atrophy was a significant neuroimaging predictor of early post-stroke cognitive dysfunction in the Nigerian African stroke survivors. These observations have implications for a vascular basis of MTA in older stroke survivors among sub-Saharan Africans.

Internal jugular phlebectasia in an African adult.

Jugular vein phlebectasia is a rare venous anomaly commonly presenting as a unilateral neck swelling in children and adults. Its aetiology is unknown and its detection may have increased with availability of better imaging facilities. Due to its rarity, a high index of suspicion is required once other causes of neck swelling are excluded. The few reported cases are mainly in children and non-Africans adults. The authors report the case of a 54-year-old Nigerian woman presenting for the first time with a progressive, intermittent, painless right neck swelling, which was demonstrated on Doppler ultrasound and CT angiography to be an internal jugular phlebectasia. She had satisfactory surgical excision of the dilated segment for cosmetic reasons.