Background: A stroke or cerebrovascular accident is associated with defects in the circle of Willis. The present research assessed whether differences in the anatomy of the circle of Willis were implicated in subjects affected by stroke. Materials and methods: A retrospective descriptive (cohort) study of images of 340 male and female subjects aged 15 to 75 years, referred for either brain Computed Tomography Angiography (CTA) or Magnetic Resonance Imaging (MRI) scan indicative of suspected stroke, was employed. A convenient sampling technique was used to obtain images from selected hospitals and radio-diagnostic centers with Computed Tomography (CT) and MRI scanners. Approval was obtained from the Federal Health Research Ethics Committee in accordance with institutional guidelines and principles, following permission and clearance (Approval Number: FHREC/2019/01/51/13-05-19). Patterns of morphology observed in the circle of Willis were data collected and stored in a non-identifiable format. Data obtained were analyzed with the Statistical Package for Social Science (SPSS) Inc, Chicago, IL, USA version 25.0. Results: Of the total 340 images evaluated, 256 (75.29%) subjects had ischemic stroke while 84 (24.71%) subjects had no stroke and were thus, considered to be apparently normal. Structural patterns in the circle of Willis mostly observed were the absence of the anterior communicating artery (10.94%) and the bilateral absence of the posterior communicating artery (10.16%). Conclusion: Morphological patterns of the cerebral arterial circle of Willis observed, were implicated in subjects affected with stroke in the present study population.

Objectives: The study investigated the equivalent dose delivered during pediatric chest radiography. Material and Methods: This study adopted a prospective and cross-sectional research design and was conducted between April 26 and July 2, 2021, at the University of Calabar Teaching Hospital, Calabar, Cross river state, Nigeria. A total of 85 pediatric patients aged 0–15 years, referred for chest X-ray examination, were recruited into the study. The chest radiography was taken for each child in erect or supine positions. Children, who needed some form of immobilization, were immobilized and respiration (breathing) was observed to take exposures at end-expiration. Exposure factors used ranged between 40 and 80 kVp, 1–2 mAs, source-to-image distance; 110 cm. Patient demographics and chest X-ray exposure factors for each exposure were recorded using a spreadsheet. The equivalent dose was calculated using the NUTECHRX software version. All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) version 21.0. Statistical significance was set at P < 0.05. Results: The estimated mean equivalent dose was 0.0046 ± 0.0026 mSv, while the mean of weight (kg), kVp, and mAs was 15.04 ± 14.51 kg, 58.28 ± 10.58V, and 1.79 ± 1.56 mAs, respectively. Mean equivalent dose was 0.00447mSv (uncertainty 0.0027) for female and 0.00464mSv (uncertainty 0.0026) for male, with no significance difference between them. The mAs showed strong positive correlation with equivalent dose (r = 0.71, P = 0.05), while weight demonstrated a strong negative correlation with equivalent dose (r = −0.98, P = 0.05). Conclusion: Current-time product (mAs) and the weight of a child are important determinants of equivalent dose in pediatric chest radiography.