Contrast-enhanced CT is a primary tool in emergency departments for diagnosing acute aortic dissection, demonstrating high sensitivity and specificity. However, artifacts such as streak artifacts can mimic aortic dissection, leading to misdiagnosis. Here, we report a case involving a 21-year-old male who sustained traumatic injuries after a motor vehicle accident. Initial contrast-enhanced CT indicated a possible localized dissection in the descending aorta. Conservative treatment was initiated under the presumption of aortic dissection. Upon re-evaluation with ECG-gated CT, the previously identified "dissection" artifact had disappeared, revealing no actual aortic injury. This case illustrates how heartbeat-induced streak artifacts, while commonly seen in the aortic root, can also manifest in the descending aorta. Our findings underscore the importance of considering artifacts in atypical cases of aortic dissection, particularly when findings are localized to areas of the aorta in close proximity to the heart. For trauma patients, while dynamic contrast-enhanced CT remains standard, ECG-gated CT should be selectively applied where motion artifacts are suspected. This case highlights the role of advanced imaging options in distinguishing between true aortic pathology and artifacts, aiding in appropriate clinical decision-making.