Imaging-based disease pattern in a consecutive series of cranial CTs and MRIs in a rural and an urban Tanzanian hospital: a comparative, retrospective, neuroradiological analysis.

The prevalence of neurological diseases and cranial pathologies in sub-Saharan Africa remains a very little investigated field. This study aims at providing an imaging-based overview of cranial pathologies in two Tanzanian hospitals and at identifying possible differences in the spectrum of diseases between rural and urban African populations. At rural Haydom Lutheran Hospital (Manyara region) the data of 726 patients were included in a retrospective survey. At urban Aga Khan Hospital (Dar es Salaam) the data of 1975 patients who had undergone Computed Tomography (CT) and of 537 Magnetic Resonance Imaging (MRI) patients were obtained. All three surveys showed a clear male preponderance within the populations. The median age of the patients was higher in the city (urban CT 48 years; range 0-95/MRI 39 years; 0.1-89; rural CT 32 years; 0-102). In the urban series stroke, extracranial infections, cerebral atrophy and tumours formed the main groups of diagnoses. Amongst rural patients traumatic pathologies, followed by stroke and cerebral infections/infestations were the most common diagnoses. The most striking differences were noticed with cases compatible with cerebral infections/infestations and hydrocephalus being reported more frequently in the rural population. On the other hand stroke and cerebral atrophy were more frequent amongst urban patients. In the rural catchment area the data of 51 HIV-positive CT patients could be obtained, showing a clear female preponderance. Within the urban HIV-positive subgroup of CT patients (n = 57), the gender distribution was almost equal. Furthermore, in both HIV-positive populations the proportion "compatible with cerebral infections/infestations" was higher than amongst the overall study populations. In conclusion, cranial pathologies seem to differ widely in rural and urban areas of Tanzania in particular with respect to cerebral infections and vascular disease.