Background: Up to 40% of ischemic stroke patients have negative results in their stroke etiologic workups, being classified as a cryptogenic stroke. In this study, we investigated carotid arteries using carotid duplex ultrasonography to identify coexisting atherosclerotic change in cryptogenic ischemic stroke patients.
Methods: We consecutively enrolled patients with cryptogenic ischemic stroke according to the TOAST classification. Normal controls were obtained at the same period. Carotid duplex ultrasonography was performed as a stroke workup. We obtained data about demographics, classical stroke risk factors, duplex ultrasonography and brain imaging. Intima-media thickness (IMT) and the character of carotid plaque (thickness, echogenicity) were measured with duplex ultrasonography. CT or MR angiography was reviewed to check arterial stenosis.
Results: A total of 67 cryptogenic stroke patients and 118 normal controls were enrolled. 36 (53.7%) of cryptogenic stroke patients and 29 (24.6%) of normal controls had carotid plaque. The plaque thickness was 2.8±1.1 and 2.3±0.2 (mm, mean, SD) respectively. Carotid plaque which is located at the parent artery of the index stroke lesion was observed in 21 patients (31.3%). Among cryptogenic stroke patients, isoechoic plaque was observed in 23 patients, hypoechoic in 6, mixed in 3, and calcified in 4. Carotid artery was normal in CT or MR angiography in 27 patients. Among them, 16 (59.2%) patients had atherosclerotic plaque.
Conclusions: About a half of cryptogenic acute ischemic stroke patients have carotid atherosclerotic plaques. The evaluation of coexisting carotid atherosclerosis with carotid duplex ultrasonography seems to be important.

Journal of Neurosonology 6(1):6-10, 2014
Key Words: Cryptogenic, Stroke, Carotid atherosclerosis, Ultrasonography