T he management of blunt cerebrovascular injuries (BCVIs), including low-grade blunt carotid artery injuries (BCIs), remains controversial; however, antiplatelet agents or anticoagulation continue to be firstline treatments, with endovascular stenting typically reserved for symptomatic or higher-grade injuries. 5,7,8,16,19,26 Whereas our earlier reports explored blunt vertebral artery injuries (BVIs), this current report presents our evaluation of Grade 1 and 2 BCIs. Imaging, progression of injury, and outcomes of these lower-grade BCIs were analyzed to abbreviatioNs ASA = acetylsalicylic acid; BCI = blunt carotid artery injury; BCVI = blunt cerebrovascular injury; BVI = blunt vertebral artery injury; CTA = CT angiography; DSA = digital subtraction angiography; MVC = motor vehicle collision. obJect Proper screening, management, and follow-up of Grade 1 and 2 blunt carotid artery injuries (BCIs) remains controversial. These low-grade BCIs were analyzed to define their natural history and establish a rational management plan based on lesion progression and cerebral infarction. methods A retrospective review of a prospectively maintained database of all blunt traumatic carotid and vertebral artery injuries treated between August 2003 and April 2013 was performed and Grade 1 and 2 BCIs were identified. Grade 1 injuries are defined as a vessel lumen stenosis of less than 25%, and Grade 2 injuries are defined as a stenosis of the vessel lumen between 25% and 50%. Demographic information, radiographic imaging, number of imaging sessions performed per individual, length of radiographic follow-up, radiographic outcome at end of follow-up, treatment(s) provided, and documentation of ischemic stroke or transient ischemic attack were recorded. results One hundred seventeen Grade 1 and 2 BCIs in 100 patients were identified and available for follow-up. The mean follow-up duration was 60 days. Final imaging of Grade 1 and 2 BCIs demonstrated that 64% of cases had resolved, 13% of cases were radiographically stable, and 9% were improved, whereas 14% radiographically worsened. Of the treatments received, 54% of cases were treated with acetylsalicylic acid (ASA), 31% received no treatment, and 15% received various medications and treatments, including endovascular stenting. There was 1 cerebral infarction that was thought to be related to bilateral Grade 2 BCI, which developed soon after hospital admission. coNclusioNs The majority of Grade 1 and 2 BCIs remained stable or improved at final follow-up. Despite a 14% rate of radiographic worsening in the Grade 1 and 2 BCIs cohort, there were no adverse clinical outcomes associated with these radiographic changes. The stroke rate was 1% in this low-grade BCIs cohort, which may be an overestimate. The use of ASA or other antiplatelet or anticoagulant medications in these low-grade BCIs did not appear to correlate with radiographic injury stability, nor with a decreased rate of cerebral infarction. Although these data suggest that these Grade 1 and 2 BCIs may require less intensive r...