Clinical and Anatomical Characteristics of Ischaemic Stroke Patients Undergoing Non-Contrast CT in a Nigerian Multicentre Cohort: Evidence of a Prolonged Stroke Onset-to-CT Scan Interval.

Abstract

Background: Ischaemic stroke is a major cause of death and long-term neurological disability, and clinical outcomes are strongly affected by the interval between symptom onset and definitive assessment. Non-contrast computed tomography (NCCT) remains the principal initial neuroimaging examination for suspected acute stroke because it is rapid, widely available, relatively inexpensive, and effective for excluding intracranial haemorrhage. However, in resource-constrained settings, patients may reach diagnostic facilities several hours or days after stroke onset, thereby reducing opportunities for acute reperfusion therapy. This study describes the demographic, temporal and anatomical characteristics of patients with ischaemic stroke who underwent NCCT in a Nigerian cohort, with particular emphasis on evidence of delayed presentation. Methods A prospective cross-sectional study was done among patients with clinically diagnosed ischaemic stroke who underwent NCCT at three diagnostic centres in southeastern and south-southern Nigeria: St. Charles Medical Diagnostics Limited, Awka; Image Diagnostics, Owerri; and Image Diagnostics, Port Harcourt. The study period extended from December 2025 to May 2026. A total of 197 patients with radiologically confirmed ischaemic stroke were included. Demographic characteristics, post-ictal imaging interval, and anatomical distribution of cerebral infarction were evaluated. Stroke lesions were classified according to the documented interval between ictus and CT examination. Descriptive statistics were used to characterize the cohort. Results The study population comprised 197 patients, including 98 males (49.7%), 98 females (49.7%) and one patient with unrecorded sex. The mean age was 61.3 ± 12.6 years, with an age range of 27–90 years. Patients aged 60 years or older constituted 56.3% of the cohort. The mean post-ictal interval between stroke onset and CT imaging was 77.5 ± 34.8 hours, demonstrating substantial delay between symptom onset and neuroimaging assessment. Anatomically, extensive or multiple cerebral involvement was the most frequent CT finding, occurring in 49 patients (24.9%), followed by basal ganglia infarction in 44 patients (22.3%). General or unspecified cerebral involvement accounted for 36 cases (18.3%), while parietal lobe infarction occurred in 25 cases (12.7%). Other sites included the occipital lobe (5.6%), thalamus (5.1%), periventricular/intraventricular regions (3.0%), frontal lobe (3.0%), insular cortex (1.5%), cerebellum (1.5%) and temporal lobe (0.5%). Conclusion This Nigerian NCCT cohort demonstrated a substantial burden of delayed presentation with the mean imaging interval occurring well beyond the conventional early treatment windows for acute reperfusion therapy. Older adults constituted the majority of the study population, while extensive/multifocal and basal ganglia involvement were the predominant anatomical patterns. The findings underscore the importance of improving stroke recognition, referral pathways, transportation, emergency imaging access, and early presentation in Nigerian stroke care. Routine NCCT remains an important and practical imaging tool in this setting and may provide a foundation for quantitative imaging approaches aimed to improving the characterization of infarct evolution.