Analytical Study of CT Pulmonary Angiography Diagnostic Accuracy and Radiation Dose at Tertiary Hospitals in South West Nigeria

CT pulmonary angiography has become the first-line investigation for pulmonary embolism diagnosis, and its diagnostic accuracy and radiation dose performance in South West Nigerian tertiary hospitals requires analytical evaluation given the dual imperative of diagnostic quality and dose management in this high-dose procedure category. This study analytically evaluates the diagnostic accuracy and radiation dose of CTPA examinations at tertiary hospitals in Lagos, Ogun, and Oyo States. A retrospective correlative design reviews 280 CTPA examinations from 2021 to 2023, evaluating technical adequacy against established CTPA quality criteria (pulmonary trunk enhancement above 200 HU, minimal respiratory artefact), diagnostic accuracy against clinical composite reference standard (Wells score probability plus D-dimer clinical correlation), and radiation dose (DLP and effective dose) against European diagnostic reference levels. Descriptive statistics, sensitivity and specificity calculations, and comparison of dose values against reference levels are performed in SPSS. Available CTPA literature from South West Nigerian hospitals identifies technically inadequate examinations attributable to suboptimal contrast timing as the primary accuracy limitation, with DLP values significantly above European reference levels. The ESR/ERS technical standards for CTPA and ICRP Publication 102 CT dose guidance provide the analytical framework. Findings are expected to identify technical inadequacy in 20 to 30 percent of examinations and DLP values exceeding reference levels in the majority. Recommendations address bolus tracking CT protocol implementation, weight-based contrast injection protocols, and dose area product monitoring at South West Nigeria CTPA departments. Keywords: CTPA, pulmonary embolism, diagnostic accuracy, radiation dose, South West Nigeria.