Background <p>Identifying the anatomical source of infection in emergency department (ED) patients with suspected sepsis is challenging. This study evaluates the radiological detection rate of thoracoabdominal computed tomography (TACT) and its association with downstream clinical management.</p> Methods <p>In this retrospective cohort study, 267 adult ED patients who underwent TACT for suspected severe infection were evaluated. The primary outcome was the radiological detection of an infectious focus, confirmed by a composite reference standard (CT findings, microbiology, clinical follow-up, and treatment response). Demographic data, quick Sequential Organ Failure Assessment (qSOFA) scores, and biomarkers were analyzed alongside clinical outcomes, including hospital admission and the need for interventional procedures.</p> Results <p>The radiological detection rate of TACT for a definitive infectious focus was 41.2% (<i>n</i> = 110), while non-infectious acute pathologies mimicking sepsis were identified in 18.0% (<i>n</i> = 48). Thoracic infections were the most common (54.5%). Multivariate logistic regression identified a qSOFA score ≥ 2 (OR = 3.14; <i>p</i> = 0.009) and elevated C-reactive protein (OR = 1.009; <i>p</i> = 0.034) as independent predictors of a positive CT scan. Patients with a radiologically confirmed infectious focus underwent source-control interventions more frequently than those with normal CT findings (14.8% vs. 2.9%; OR = 5.72, <i>p</i> = 0.014). The detection of any pathological finding on CT was strongly associated with hospital admission.</p> Conclusion <p>TACT is a valuable diagnostic tool in suspected infections. High qSOFA scores and CRP levels correlate with a higher probability of detecting an infectious focus on CT. Beyond primary diagnosis, positive TACT findings are strongly associated with hospital admission and facilitate targeted source-control interventions.</p>