Background: Although a residual intimal tear may contribute to the dilatation of the descending aorta following surgical repair of acute type I aortic dissection (AD), its causal relationship has not been elucidated by clinical data due to the limited resolution of imaging modalities. Methods: This study enrolled 41 patients (age, $55.2{pm}11.9$ years) who were evaluated with dual-source computed tomography (CT) imaging of the whole aorta in the setting of the surgical repair of acute type I AD. Logistic regression models were used to determine the predictors of a composite of the aortic aneurysm formation (diameter >55 mm) and rapid aortic expansion (>5 mm/yr). Results: On initial CT, a distal re-entry tear was identified in 9 patients. Two patients failed to achieve proximal tear exclusion by the surgery. Serial follow-up CT evaluations (median, 24.6 months; range, 6.0 to 67.2 months) revealed that 14 patients showed rapid expansion of the descending aorta or aortic aneurysm formation. A multivariate analysis revealed that the residual intimal tear (odds ratio [OR], 4.31; 95% confidence interval [CI], 1.02 to 19.31) and the patent false lumen in the early postoperative setting (OR, 4.64; 95% CI, 0.99 to 43.61) were predictive of the composite endpoint. Conclusion: The presence of a residual intimal tear following surgery for acute type I AD adversely influenced the expansion of the descending aorta.