Extravascular optical coherence tomography: Evaluation of carotid atherosclerosis and pravastatin therapy

BACKGROUND AND PURPOSE - : Extravascular optical coherence tomography (OCT), as a noninvasive imaging methodology with micrometer resolution, was evaluated in a murine model of carotid atherosclerosis by way of assessing the efficacy of pravastatin therapy. METHODS - : An OCT device was engineered for extravascular plaque imaging. Wild-type mice and apolipoprotein E-deficient (ApoE) mice were randomized to 3 treatment groups: (1) wild-type on a diet of standard rodent chow (n=13); (2) ApoE on a high-fat, atherosclerotic diet (HFD; n=13); and (3) ApoE on a HFD given daily pravastatin (n=13). Mice were anesthetized and the left common carotid was surgically exposed. Three-dimensional (3D; 2 spatial dimensions+time) and 4D (3 spatial dimensions+time) OCT images of the vessel lumen patency were evaluated. After perfusion, in situ OCT imaging was performed for statistical comparison with the in vivo results and final histology. RESULTS - : Intraoperative OCT imaging positively identified carotid plaque in 100% of ApoE mice on HFD. ApoE mice on HFD had a significantly decreased lumen patency when compared with that in wild-type mice (P<0.001). Pravastatin therapy was found to increase lumen patency significantly in ApoE mice on HFD (P<0.01; compared with ApoE on HFD). The findings were confirmed with OCT imaging after perfusion and histology. CONCLUSIONS - : OCT imaging offers the potential for real-time, detailed vessel lumen evaluation, potentially improving surgical accuracy and outcomes during cerebrovascular neurosurgical procedures. Pravastatin significantly increases vessel lumen patency in the ApoE mouse on HFD.