Dynamic contrast-enhanced MR imaging of carotid vasa vasorum in relation to coronary and cerebrovascular events.

BACKGROUND AND AIMS: Dynamic contrast-enhanced MR imaging (DCE-MRI) provides a noninvasive approach to the functional status of carotid adventitial vasa vasorum. Contrast extravasation rate, or Ktrans , derived from kinetic modeling of adventitial enhancement, has been correlated with plaque neovascularization and inflammation. This study sought to clarify the clinical implications of Ktrans by evaluating its relationship with documented cardiovascular events (CVE).

METHODS: Seventy patients with carotid plaque at clinical ultrasound examination were recruited and imaged with a previously-described bright-blood DCE-MRI protocol (spatial resolution: 0.55 × 0.58 mm2 ; time resolution: 18 s). Patients were classified by the presence of documented coronary and/or cerebrovascular events. Adventitial Ktrans was estimated via kinetic modeling of outer wall enhancement as captured by DCE-MRI.

RESULTS: After excluding six patients with insufficient image quality, 64 patients (66 ± 12 years, 51 male) had DCE-MRI measurements. Patients with documented CVE showed significantly higher adventitial Ktrans than those without (0.056 ± 0.024 versus 0.034 ± 0.008 min-1 , p < 0.001), whereas comparable measurements were seen among the subgroups with CVE (p > 0.05): 0.054 ± 0.027 min-1 in patients with coronary events alone, 0.056 ± 0.018 min-1 in patients with cerebrovascular events alone, and 0.069 ± 0.022 min-1 in patients with both. Carotid adventitial Ktrans was negatively correlated with time since clinical event (Spearman's rho = -0.40, p = 0.003).

CONCLUSIONS: Patients with documented CVE demonstrated increased rate of contrast extravasation from carotid adventitial vasa vasorum on DCE-MRI irrespective of the territory of events. Systemic factors implicated in the pathophysiology of acute atherothrombotic events may influence the functional status of adventitial vasa vasorum.