Background Cardioembolism has tendency to recur and cause lesions in distinct cerebrovascular territories. Using the imaging characteristics of cerebral lesions to determine dissemination in time and space (DTS) is a concept already used in other neurologic conditions; however, it has never been applied as a diagnostic tool in ischemic stroke etiology. Aim This study aimed to assess DTS as a diagnostic marker of cardioembolism. Methods We enrolled consecutive patients with acute ischemic stroke of various etiologies admitted in a cerebrovascular disease nursery from a university hospital in a retrospective cohort study. We excluded patients with coexisting etiologies, incomplete study, or without an acute vascular lesion on computed tomography scan. Lacunar infarctions were not considered. Cerebrovascular territory was divided into right anterior, left anterior, and posterior. Localization of the acute vascular lesion(s), existence of previous vascular lesions, and their respective areas were analyzed. The presence of dissemination in time, space, or DTS was determined. Results We included 661 patients (mean age: 74.05 years (SD: 13.01)). Cardioembolism was the etiology with most DTS (30.47% of cardioembolic strokes); DT occurred more frequently within the atherosclerotic subtype (9.88%); DS was more prevalent within the arterial dissection group (3.33%). There was a statistically significant difference in stroke etiology between patients with DTS and patients without dissemination ( P  < .001). DTS had 81.67% specificity, 30.47% sensitivity, 66.67% positive predictive value, and 49.40% negative predictive value for the identification of cardioembolism. Conclusion DTS is a specific diagnostic predictor of cardioembolic stroke and may be helpful in guiding etiologic investigation.